Question

if the area of a rectangle is 3x^2+9x, what is the length if the width is 3x?

Answer 1

Given

The area of the rectangle is 3 x ^ 2 + 9 x  sq units.

The width of a rectangle is ( 3 x ) units .

Let the length of a rectangle is  l

The area of the rectangle = length * width.

( 3 x ^ 2 + 9 x )  = l * (3 x)

(3 x ^ 2 + 9 x ) / ( 3 x ) = l

[ ( 3 x ^ 2 ) / 3 x ] + [ ( 9 x ) / 3 x ] = l

x + 3 = l 

Therefore length ( l ) =( x + 3 ) units.

Solution : The length of a recangle ( l ) = ( x + 3 ) units.